The best example of this is Ford's line of EcoBoost engines, which started with a 3.5-liter turbocharged V-6 with the same power and towing capacity as the larger V-8 it replaced in Ford's best-selling F-150 pickup truck.

That engine has been a surprise, selling much better than Ford expected, especially in full-size pickup trucks.

It was joined by a 2.0-liter four that replaces a 3.0- to 3.5-liter V-6, and then by both 1.5- and 1.6-liter fours that replace larger standard 2.5-liter fours.

Most recently, Ford has added a 1.0-liter three-cylinder turbocharged engine, which replaces a conventional four of up to 1.6 liters.

And, who knows, there may be more to come.

The downside of smaller turbo engines is that they're more economical under light load than the bigger ones they replace, but equally thirsty at high power.

So aggressive drivers may find them thirstier than their EPA ratings, while gentler souls do just fine.

Few V-8s outside trucks

By 1970 or so, even so-called compact sedans offered V-8 engines. The only sixes were on base models, and four-cylinder engines from U.S. makers were a rarity.